Arsonium and stibonium anion exchangers

ABSTRACT

Anion exchangers characterized by superior and unique properties are provided which are polystyrene-divinylbenzene copolymers having an exchange group in the molecule, the exchange group being an &#39;&#39;&#39;&#39;-CH2X R&#39;&#39;&#39;&#39; group (wherein X is an As or Sb atom, and R is a methyl group).

United States Patent m] Ito et al. 1 Jan. 16, 1973 I [54] ARSONIUM AND STIBONIUM ANION v OTHER PUBLICATIONS EXCHANGERS 4 p Tros tyanskaya et al., J. Polym. Sci. 59, 378-87 387 [75] Inventors: Takuji Ito, Setagaya-ku, Tokyo; (1962). I r

Yoshio Hoshino, Fuchu-shi, Tokyo, Trostyanskaya et al., Zh. Prikl. Khim. 39, 1754-1760 both of Japan (1966). 1 Trost anska et al., V sokom 1e 1. S d 5, [73] Asslgneez Tokyo Institute of Technology, 3254229 y o 0e m Japan Kim, Daehan Hwahak Hwoejee 14, 37-43 1970 [22] Filed: March 22, 1971 Primary. Examiner-Melvin Goldstein [21] Appl' N05 126,945 Atl0rney-Burgess, Ryan & Wayne [30] Foreign Application Priority Date [57] ABSTRACT March 27 1970 Japan ..'.45/26383 "xchmgers characterized by SuPerior and I unique properties are provided which are polystyrene- [52] U S 260/2 1 E 260/88 2 C divinylbenzene copoiymers having an exchange group [51] Co8 19'/2o in the molecule, the exchange groupbeing an v-'Cl'l' t 1 H l E x+Rn group (wherein x is an As or atom and R is v a methyl group).

[56] References Cited I 3 Claims, No Drawings '1 ARSONIUM ANDSTIBONIUM ANION EXCHANGERS BACKGROUND OF THE INVENTION Jana, H

wherein R is a methyl group or a hydroxyethyl group. Said plystyrene-divinylbenzene copolymer is a polystyrene resin containing divinylbenzene as a cross linking agent and having generally a degree of cross j linking of from 4 to 8 percent. Such polystyrenedivinylbenzene copolymers may be synthesized by a conventional method.

The above-mentioned anion exchangers are sold by Dow Chemical Co. (United States of America) under the trademarks e.g. Dowex l," or Dowex 2 or Dowex 3. I

- For example, Dowex l-X4 i s a strongly basic anion exchanger which is a polystyrene-divinylbenzene copolymer having 4 percent of a degree of cross linking with divinylbenzene and an exchange group of Cl-l, N R in the molecule (R being methyl group). The properties of anion exchangers are generally compared in ion-exchange capacity (meq/g), distribution coefficient (Kd), separation factor (a) and selectivity coefficient (K characterized in that they have the above-mentioned wherein X is an arsenic or antimony atom and R is a methyl group. v

The novel anion exchangers of this invention are exchange group in the molecule in place of the exchange group of Dowex l-X4 as apparent from the above-mentioned fonnula, the exchange group of the novel anion exchangers of the present'invention con tain an arsenic (As) or antimony (Sb) atom therein in place of the nitrogen (N) atom in the exchange group of Dowex l-X4 anion exchange resin.

ln-this specification, the anion exchangers containing said As or Sb atom in the exchange group are, hereinafter, referred to as arsonium-type anion exchangers or stibonium-type anion exchangers, respectively.

The process for synthesizing the anion exchanger of this invention comprises the steps of adding a non-polar solvent to a chloromethylated polystyrene-divinylbenzene copolymer, adding a polar solvent-to the resulting solution and then adding thereto a solution of 'j' These terms are 'aenaaa TE CLB. Wmph'ietfinorganic IonExchangers, Elsevier, Amsterdam, 1964.

Anion exchangers having a preferred separation factor which is adequate for separating one anion from others in a mixture of various anions,-and possessing a unique selectivity coefficient were desired.

It is, therefore, an object of the present invention to provide anion exchangers having such desirable and superior properties.

wehaveThuhd tha t fhehdvefahion "exehafigafiraving the aforesaid desirable superior properties can be obtained by replacing the nitrogen atom with an arsenic' atom or antimony atom in the exchange group of the polystyrene-divinylbenzene copolymer.

The present invention is based on this discovery.

trimethylarsine or trimethylstibine in ether, allowing the chloromethylated polystyrenewdivinylbenzene copolymer to react with trimethylarsine or trimethylstibine under reflux at a temperature of from 35 to C, and removing the aforesaid solvents from the reaction product.

Suitable non-polar solvents include benzene, carbon tetrachloride or hexane, and suitable polar solvents include dichloromethane, trichloromethane or ethylidene chloride.

Preferred embodiments of the process for synthesizing the anion exchangers of this invention are set out in the following examples which are to be considered as illustrative and not limiting. 1

EXAMPLE 1 Synthesis of the Arsonium-type Anion Exchanger 20cc of benzene and 20cc of dichloromethane were 7 ture of from 35 to 45C under reflux for 2 days.

The reaction product was washed with acetone, ethyl 5 alcohol and water in turn. 18.8g of the arsonium-type anion exchanger were obtained. The anion exchanger thus obtained had an ion-exchangecapacity of 1.54 meq/g.

3 EXAMPLE 2 Syntheses of the Stiboniurn-type Anion Exchanger 20cc of benzene and 20cc of dichloromethane were added to g of chloromethylated polystyrene-divinyl- H benzene copolymer which has been made by a conven tional method, and to this was added ZOOmeq/g. of a solution containing 1.5 mol of trimethylstibine in 1 liter of ether. The resulting mixture was stirred-at a temperature of from 35to 45C under reflux for 2 days.

' The "re'iidn"piiiiiiifikasfivashed in turn with acetone, ethyl alcohol and water. 19.5g of the stiboniexchanger thus obtained had an ion-exchange capacity of 1.31 meg/g.

The properties of the arsonium-type or stiboniumtype anion exchangers of this invention obtained as abovewill be compared with those of the conventional anion exchanger such as Dowex l-X4.

The properties of Dowex l-X4, the Arsonium-type 'exchanger and the Stibonium-type exchanger are shown in the tables 1 and 2 below and the accompanying drawings, in which-FIG. l and FIG. 2 are titration curves-of the arsonium-type anion exchanger and the stibonium-type anion exchanger, respectively.

From FIG. 1 and FIG. 2, it will be understood that the arsonium-type and the stibonium-type 1 anion exchanger of this invention are strongly basic.

Distribution coefficient (Kd) and separation factor um-type anion exchanger were obtained. The anion (a) of. the anion exchangers (NO -form) to several anions (Cl, Br", I and SCN') are shown in the table 1 below.

TABLE 1 Stibonium-type Arsonium-type anion exchanger Dowex l-X4anion exchanger Kda Kan Kda c1- 31 19 v 6.1 12.5 }4.2 2.3

Br' 79 so 14 a }4.4, lss 7.9 1- 351 50s 110 '-}1 }2.4 2.7 SCN- 615 1210 297 Conditions of measurement: l NO -form anion exchanger: 0.4g

2 Concentration of Cl, Br, I' or SCN': 1.6Xl0

3meq. 3 Said ingredients (1) and (-2) are added to 0. l N:

KNO solution to prepare a solution of 25.0cc. 4 Temperature: 25C 5 Standing time for ion exchanging: 20 hours 6 Color reagent: A mixture-of dil-HNo an aqueous solution of potassium iron sulfate andan alcoholic solution of mercury thiocyanate 7 Wave length for measurement: 460 my. 8 Measuring apparatus: Spectrophotometer sold by 4 Hitachi Seisakusho (Japan) under Type EPU- 2A 1 As is evident from the above-mentioned data, the arsonium-type and the stibonium-type anion exchangers of this invention have a significantly higher ability of separation than that exhibited by Dowex l-X4.

The orders of the selectivity coefficients (K'Cl) of various anions vs. chlorideion with the anion exchangers are shown in table 2 below.

and the stibonium-typeanion exchangers clearly exhibit a different selectivity from that of Dowex l-X4. It is clear from the above-mentioned results of the comparison tests that the arsonium-type and the stibonium-type anion exchangers of the invention have superior and unique properties in comparison with a conventional quaternary exchanger such as Dowex l-X4.

We claim:

I. An anion exchanger which is polystyrene-divinylbenzene copolymer having an exchange group in the molecule thereof, characterized in that said exchange group is a group having the following general formula:

wherein X is an arsenic or antimony atom, and R is a methyl group.

2. An anion exchanger according to claim 1 wherein X is an arsenic atom.

3. An anion exchanger according to claim 1 wherein X is an antimony atom.

ammonium-type anion UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,711,429 Date d January 16, 1973 Inventor(s) Takuji Ito, et a1 It is certified that error appears in the aboveeidentified patent and that said Letters Patent are hereby corrected as shown below:

Column 3, lines 5l52"'l.6 X 10 3meq" should read 1.6 x 10" meq Insert the attached sheet as part of the Letter Patent- Signed, and sealed this 20th day of August 197 (SEAL) Attest:

" Y M. GIBSON JR. C. MARSHALL DAN'N A i sting Officer Commissioner of Patents USCOMM-DC 60376-P69 FORM PO-1050 (10-69) I Y 1* ms GOVERNMENT ram'rma OFFICE: Ion o-acs-au.

January 16, 1973 Patent -.T3,711,'429

" Page 2 HCI meqmdded) HCI meq (Added) 

2. An anion exchanger according to claim 1 wherein X is an arsenic atom.
 3. An anion exchanger according to claim 1 wherein X is an antimony atom. 